The overall aim of this work is to understand the biochemical effects of androgens or testicular cells and to relate these to the effects of FSH and to the control of the spermatogenic process. The approach will involve delineation of similarities and differences between the protein synthetic response of Sertoli and peritubular cells using 35S-Met- labeling and 2D-PAGE. The cellular localization and regulation of testicular gamma-glutamyl transpeptidase mRNA will be studied with the use of cDNA probes. cDNA probes for hormonally regulated Sertoli cell mRNA will be isolated using 32p-Sertoli cell cDNA enriched for hormone- dependent messages by subtractive prehybridization with respect to sequence and subcloned into open reading frame vectors and the resulting tribrid proteins used to prepare antibodies. The antibodies in turn will be used to determine the subcellular localization and possible identity of the corresponding protein. These studies should increase our understanding of the hormonal control of Sertoli cell functions and provide new insight into aspects of the functions which may relate to the control of spermatogenesis.